Seat belt retractor mechanisms undergo continual improvement in an effort to make them more prone to use by vehicle occupants and, hence, more effective. A major improvement was the addition of a ratchet mechanism to selectively prevent retraction of the seat belt webbing onto the spool. By so doing, the belt can be worn in a tensionless mode by the vehicle occupant, providing an unencumbered feeling. Generally, to release the ratchet mechanism, a locking pawl must be disengaged from a ratchet wheel. The ideal operating conditions are such that when the seat belt is protracted and latched, the pawl is firmly engaged with the ratchet wheel to prevent retraction motion. Likewise, in this engaged and locked state, the pawl should resist undesired disengagement from the ratchet wheel. On the other hand, when it is desired to remove and retract the seat belts--the tensioned mode-the pawl should disengage from the ratchet wheel with a minimum amount of force. Several mechanisms are currently employed for selecting between the tensioned and tensionless modes of operation.
One such mechanism is described in U.S. Pat. No. 3,973,786 by Rogers, Jr., issued Aug. 10, 1976, and assigned to General Motors Corporation. Rogers discloses a belt retractor for a vehicle occupant restraint system which has a winding prevention mechanism which is interlocked to the vehicle door so as to cancel the winding prevention mechanism when the door is opened. In apparatus such as Rogers, a complex cluster of discs, clutches, ratchet wheels, and pawls operates as the winding prevention mechanism for a conventional springbiased winding spool belt retractor. Actuation and cancellation of the winding prevention mechanism is made responsive to a predetermined sequence of belt winding and unwinding movements which the user must perform. A mechanical linkage between a door activated plunger and the complex winding prevention mechanism moves a pawl in the mechanism between a detenting and undetenting positions whereby a tensionless mode can be instituted when the door is closed. A similar device is shown in U.S. Pat. No. 4,065,072 by Magyar, issued Dec. 27, 1977, also assigned to General Motors Corporation.
Wherefore, it is an object of the present invention to provide an improvement to mechanisms used with a seat belt retractor for selecting between a tensioned and tensionless mode of operation.
It is a further object of the present invention to provide a simple and reliable apparatus for a seat belt retractor for selecting between a tensioned and tensionless mode.
Another object of the invention is to provide an electrically activated mechanism for a seat belt retractor for selecting between a tensioned and tensionless mode.
A further object of the invention is to provide a tensioned and tensionless mode seat belt retractor mechanism with a user accessible, electrical device for mode selection.